Shock absorbers are widely used in various types of equipment and on a variety of vehicles, such as, but not limited to, vehicle suspension systems for traveling over land. Generally, it is desirable to absorb impacts with spring systems between wheel assemblies and the main chassis of the vehicle, while providing for both compression and rebound damping to avoid excessive bounce and maintain good contact and control with the ground. However, it is also desirable to have a suspension stiff enough that it does not “bottom out” (i.e., reach the end of its compression travel) upon low-frequency high-amplitude bumps or jumps. Setting up the spring rates and damping control to deal with such large suspension hits may cause the suspension to be harsh over high-frequency low-amplitude terrain features.
Although it is desirable to develop suspension systems with a wide damping range, that preferably does not bottom out, and has an adequate stiffness to maintain traction, the process of tuning a shock absorber is regarded by many as a “black art.” In brief, the tuning process generally involves changing the shims of the compression and rebound shim stacks to create the right “feel” of the suspension system, for example increased or decreased stiffness in order to obtain a desired balance between stability and response versus comfort and traction. Those skilled in the art of tuning suspensions often rely on years of experience and an uncanny ability to “feel” or estimate the appropriate amount of stiffness for a shock absorber depending on a variety of variables, vehicle and rider weight, vehicle driving style, road conditions, rider input and other factors. It is understood that compression damping changes may be used to influence the vehicle's stability and response, while rebound damping changes may be used to influence comfort and traction.
By way of example, one method for tuning a shock absorber suggests the following steps, as follows: (1) understand the function of the shock absorber and its affect on the handling of the vehicle; (2) keep notes for each tuning step; (3) make only an incremental adjustment and then test; (4) repeat as necessary; (5) go back to the shim stack starting configuration and double check to be sure; (6) monitor any change in conditions like tire pressure, temperature, etc. This is why shock absorber tuning is considered to be a black art.